Cu(I)‐Enriched Hierarchical HKUST‐1/GO Composite: A Recyclable Catalyst for Green Azide–Alkyne Click Reactions

Abstract A simple and scalable template‐assisted strategy for synthesis of graphene oxide (GO)‐supported HKUST‐1 MOF composite (HKUST‐1/GO) as an efficient, recyclable, heterogeneous catalyst for azide‐alkyne “Click” reaction is presented. Field emission scanning electron microscopy, powder X‐ray diffraction, and X‐ray photoelectron spectroscopy analysis suggest that the use of GO as a synthetic template promotes the growth of Cu(I)‐rich hierarchical MOF structures with elongated, regular cuboidal shapes. Catalytic investigations over room temperature reaction of α ‐naphthyl azide with phenylacetylene‐as a model azide‐alkyne cycloaddition (AAC) click reaction, reveal the outstanding catalytic performance and recyclability of the HKUST‐1/GO composite. Besides the model AAC reaction, the HKUST‐1/GO composite is demonstrated to exhibit exceptionally high catalytic performance toward cycloaddition reaction of various sterically challenging and biologically relevant azide‐alkyne systems. Our investigations demonstrate that the templated growth of Cu‐MOF over GO imparts it with mixed valence active Cu catalytic sites, improved electronic conductivity, and a unique morphology that enables rapid analyte transport. These GO‐induced features confer excellent stability, recyclability, and activity to the HKUST‐1/GO composite. The exceptional catalytic performance, ease of recovery, and excellent recyclability as demonstrated for HKUST‐1/GO composite in the present work position it as a cost‐effective, efficient, and reusable heterogeneous catalyst for AAC click reactions.